class student(object):
    #pass
    '''
    if dont's have __ ,this is public func
    '''
    def __init__(self,name,score):
        self.name=name
        self.score=score
    def print_x(self):
        print ('%s:%s'%(self.name,self.score))
    def grade(self):
        if self.score>=90:
            return 'A'
        elif self.score>=60:
            return 'B'
        else:
            return 'C'
            
    